Wave guide coupling



Sept. 12, 1950 w. A. ARON ETAL WAVE cum: COUPLING 2 Sheets-Sheet 1 FiledFeb 8, 1945 WAL rm A. ARON CHARLES H 0,4 m LOWELL M. HOLL/NGSWORTHINVENTORS BY WW Q z/fi wg Sept. 12, 1950 w. A. ARON EIAL WAVE GUIDECOUPLING 2 Sheets-Sheet 2 Filed Feb. 8, 1945 FIG. l

228, 23 24& 4

WALTER A. ARON 7 CHARLES H. DAVIS LOWELL HOLLINGSWORTH IN VEN TORS-ATTORNEY Patented Sept. 12, 1950 UNITED STATES PATENT OFFICE WAVE GUIDECOUPLING Application February 8, 1945, Serial No. 576,844

This invention relates to a transmission line for high frequency energyand more particularly to a transmission line having substantialrotational flexibility. The present line maybe twisted relative to itslongitudinal axis within a wide range without introducing substantialtransmission losses.

It has been proposed, in copending application of Joseph E. Coyle andElmer L. Younker, Serial No. 534,324, filed May 5, 194.4, to provide aflexible length of line capable of being bent and also rotatable aboutits axis. The flexible length according to this copending applicationcomprises a substantial number of relatively short wave guide sections,mounted in a flexible rubber tube in spaced relation to each other. Eachsection is in the form of a metallic disk having a central openingtherein, corresponding to the dimensions of a rectangular or circularwave guide. An annular quarter wave channel constituting a highfrequency choke is provided in one face of each wave guide section.

As in the prior device mentioned above, the present invention reliesupon the fact that microwave energy may be transmitted from one sectionof a wave guide to another without substantial loss, providing somemeans are used between each section to prevent radiation. In the priordisclosure such a means takes the form of'a quarter-wave annular cavitywith the space between spaced Wave guide sections providing the channelcommunicating with the wave guide apertures so as to act as a highfrequency choke whereas in the present invention the wave guide sectionsare in abutting relation, with one face of each section undercut toprovide the space communicating with the annular cavity. The priordevice, however, is principally designed to permit bending of the line,while the present invention is concerned principally with oscillatoryrotation of one length of a wave guide relative to a stationary lengthof wave guide about their common axis.

The principal object of the present invention is to provide a length ofWave guide type of transmission line which is capable of rotationaloscillation within a, wide angular range wherein the standing wave ratioand losses will be maintained at a satisfactorily low level.

Anothe object of the invention is to provide a coupling structure orjoint between two lengths of wave guide to permit one of the lengths tobe rotated with respect to the other on an axis common to both lengths.

13 Claims. (Cl. 178-44) Still another object of the invention is toprovide means for permitting rotation between two aligned wave guideswherein the means is adapted to provide a uniform twisting action tomaintain the desired continuity of propagation or transmission of highfrequency energy from one wave guide to the other.

Another object of the invention is to provide a length of wave guidetransmission line or a coupling structure embodying a plurality ofabutting sections, each being rotatable relative to its adjacent sectionin a progressively limited manner towards one end of the length of lineor coupling. Any desired number of sections may be used, the numberdepending upon the degree of twist or rotation contemplated.

Other novel features and advantages of the invention will becomeapparent as the description proceeds.

In the drawings:

Fig. l is an elevational view of a wave guide transmission line couplingstructure according to one embodiment of the invention;

Fig. 2 is a right end view of the coupling structure of Fig. 1;

r Fig. 3 is a longitudinal horizontal sectional view of said couplingstructure, taken along the line 3-3 of said Fig. l, the elbows and someparts beyond them being omitted;

Fig. 4 is a transverse vertical sectional view of said couplingstructure, taken along the line 4-4 of Fig. 3;

Fig. 5 is a longitudinal sectional view, similar to Fig. 3, of amodified form of one of the intermediate sections shown in Fig. 3;

Fig. 6 is a right end view of the intermediate section of Fig. 5;

Fig. 7 is an enlarged, slightly exaggerated top view, partly brokenaway, of the intermediate section of Fig. 5, with a pin and wire inplace; and

Fig. 8 is a fragmentary sectional view taken along the line 8-8 of Fig.'7.

Referring now to Figs. 1-4, a length of standard rectangular typemetallic wave guide it) is joined to another length of wave guide It bya coupling structure, joint or rotationally flexible wave guide lengthgenerally designated by H.

Coupling structure l2 as shown in Fig. 3 generally comprises an endsection 13, an intermediate section a center section i5, anotherintermediate section I 6 and an end section l-I. It will be understoodthat any number of intermediate sections may be provided, preferably anequal number being positioned on each side of center section I5,depending upon the degree of oscillatory rotation desired.

Each of the aforesaid sections I3I| preferably is in the general form ofa disk or oylindrical member of brass, aluminum or other suitablemetallic substance. In a preferred embodiment (Figs. 1-4) the centersection I5 is substantially one-half wavelength in axial length and theintermediate sections are approximately a quarter wavelength long. Thesections are rotatable relative to each other and each section isprovided with a rectangular central aperture I8 (Fig. 3) correspondingin size to the wave guide dimensions used. Coupling stru-ctiu'e I2 is soassembled that each of sec tions I3, I4, I5, I6 and I! abuts itsadjacent section and all of the sections are in aligned relation so thatthe axes of the central apertures I8 are in substantial alignment.

Each of the aforesaid end and intermediate sections i3, I4, I6, I! isformed to provide a radio-frequency choke to prevent radiation, but inthe preferred embodiment the center section I5 is not formed as a chokesection. The choke comprises an annular channel or cavity I9 formed inone face of each section around aperture I8, this face being designatedas the front face. In

4 general, the inner diameter of channel I9 is just sufiicient to exceedthe diagonal dimension of aperture I8 as shown more clearly in Fig. 4.The radial width and axial depth of channel I9 must be of properdimensions to provide the desired choke action. Such a channel is knownas a quarter-wave choke, although in practice the depth of the cavitygenerally is somewhat less than a quarter wavelength. Proper dimensionsfor such a choke cavity are well-known in the art.

In order that channel l9 may function as a choke, it is necessary thatthere be communication between aperture or opening I8 and channel I9.Inasmuch as the sections are in abutting relation, with the front faceof one section engaging the rear face of the adjacent section, resort ishad to a channel 23 communicating with channel I9. undercutting thefront face of each of sections I 3, I4, I6 and I! so that there is adisk-shaped space between the undercut portion of the front face of onesection and the rear face of the adjacent section. This is more clearlyshown in Fig. 5 with respect to an individual section, here shown as amodified form of the intermediate section I l. It will be understoodthat while the following description is directed to the intermediatesection M, the structure and operation thereof applies also to the othersections except when specifically mentioned otherwise.

Disposed in the circumferential surface portion of section I4 is atleast one circular recess or socket 2|, adapted to receive a pinmember22a (see Figs. 3 and 4). In a preferred form two, recesses 2! aredisposed diametrically opposite each other although it will beunderstood that any desired number of recesses 2I and pins 22a may beused desirably spaced equally about the circumference of the section.Pins 22a are herein shown as being generally cylindrical in shape withtheir axes colinear with the radii of section I4 and are free to rotateabout their axes within recesses 2|. A neck portion 23a of each of pins22a extends out of the recesses 2I. This neck portion 23a may be of thesame diameter as that of the larger body portion 24a located within arecess 2|.

A diametrical bore 26 isdisposed through neck Channel 29 is formed bycircularly over and slidably engage the top surface of each of pins 22ato prevent outward movement thereof, as hereinafter described.

Fig. 3 illustrates the joint or coupling structure I2, according to thepreferred embodiment, in assembled position and shows the severalsections I3, I4, I5, I6 and IT in aligned abutting relation. with bores26 of pins 22 also in normally aligned relation. As the center sectionI5 is not usually provided with a choke channel, sections I 4 and I6 arein reverse relation with each other so that their front faces abut thesmooth parallel faces of section I5.

As shown, terminal or end sections I3 and I! may be provided withslightly larger apertures I! for receiving in firmly fitting relationthe ends of rectangular wave guides I0 and I I respectively, and whichmay be secured within apertures I8 in any suitable manner.

Sections I3 and II are also provided at their end portions withoutstanding annular flanges 33. The diameter of flanges 33 issubstantially equal to the diametrical distance between the outer or topsurfaces of pins 22a. A hollow cylindrical sleeve 28 is mounted onflanges 33 to surround the several sections I3-I1 of the joint orcoupling structure I2 for substantially the entire length thereof toprovide a housing therefor. Sleeve 28 is adapted to slidably engage thetops of pins 22 on each of the sections [3, I4, I5, I6 and I1, therebymaintaining the same in position and serving to make the joint orcoupling structure I2 substantially stable.

Mounted on the free end of section I3 is an annular end plate or lookingring 34, secured to section I3 by several screws 35. A rabbet 3B isprovided in the peripheral portion of the face of plate 34 adjacentsection I3 for engaging and receiving one end of sleeve 28, thuspreventing longitudinal movement thereof relative to the individualsections. Sleeve 28 may be maintained in position at the opposite end ofjoint I2 by providing an outstanding flange 31 on the righthand end offlange 33 of section I1. Flange 31 and sleeve 28 may be secured inposition by a nut 38 having an inwardly extending annular flange 33overlapping a portion of the outside face of section I! and flange 37.Nut 38 is externally knurled and internally threaded to engage anexternally threaded portion 59 at the end of sleeve 28. The nut 38 is sopositioned longitudinally relative to the sleeve 28 that the end sectionI! is free to rotate relative to said nut and sleeve and that theseveral sections I1, I3, I5, I4 and I3 are free to rotate relativetoeach' other. If desired, a lock ring 4| also may be provided forthreaded engagement with sleeve 28.

We may consider the left-hand end of joint or coupling structure I2 asthe stationary end as it is usually associated with a stationary waveguide I0 while the right-hand end may be assumed to be the oscillatoryend as it is associated with wave guide I i. which is rotatable in anoscillatory manner, about its longitudinal axis.

As wave guide II oscillates about its longitudinalv axis, section Hwhich is secured to wave uide [I rotates with it in the same directionand for the same degree of rotation. This movement carries each pin 22aof section I! in the same direction, and by pressure of said pins 22a.upon wires 2'! which are slidably engaged in the bores 26 of alignedpins 220. tends tocause wires 21 to bend. This tendency is somewhatoffset due to the fact that pressure on wires 2i causes the aforesaidpins 22: to rotate about their axes within the recesses or sockets 2|.Continued twisting or rotation of wave guide II' increases the tendencyof the wires .21 to bend. However, the wires 2.1 are preferably ofsufficiently' strong material, such as music wire, to resist bending andconsequently the wires serve as lever arms against the pins 220. in thenext adjacent section I6. to. impart a rotational movement to sectionI6. Similar motion is imparted by rotation of section I6 to the nextadjacent section I and successively to section I4 and similarly to anyadditional sections which may be included within the coupling structurei2. It will be noted that the rotation of each succeeding section lagsthat of the preceding section slightly, and that the degree of rotationof each succeeding. section is less than that of each preceding adjacentsection.

It will therefore be. understood that the wires or rods 21 serve thedual purpose of imparting rotation to the succeeding sections and oflimiting the degree of rotation between adjacent sections, It will alsobe noted that as rotation occurs the wires 21 have a tendency to slidein bores 28 of pins 2211, Or expressing it another way, the pins 22a.tend to slide longitudinally relative tothe wires 21 as they rotateupontheir axes and as the pins of adjacent sections become angularly offsetrelative to each other in the direction of angular movement. In order toprevent disengagement of the wires 27 from pins 22a in end sections I3and I1 and to insure the proper degree of rotation, wires 2'! are madesufiiciently long to extend beyond the pins 220 in sections I3 and IT.The wires 21 may also be provided with enlarged portions or knobs attheir ends. Also, if desired, each Wire 27 may be soldered or other-Wisesecured or anchored within the bore 26 of one of the pins 22a, moredesirably of the pin 22a associated with the center section it to insurethat wire 21 will remain centered with respect to the coupling structureI2, and will not be displaced longitudinally in either direction.

It is apparent that with sections I3 and I1 firmly secured to waveguides I0 and I I, respectively, and with the four rotatable sectionsI4, I5, I6, and I"! arranged as shown in Fig. 1, rotation in onedirection of wave guide II and thus of end section I I will result in aproportional relative rotation between adjacent sections. Furthermore,this proportionality of rotation between adjacent sections will maintaindesired continuity of propagation or transmission of energy through thecoupling structure or joint I2 and will result in a proportionalrotation of the direction of polarization of the transmitted energywhile maintaining the standing wave ratio and losses at a satisfactorylow level.

It will, of course, be understood that the rotatable sections of thecoupling structure or joint I-2- are adapted to. rotate in bothclockwise and counterclockwise direction relative to thencrmal fat restposition as wave guide .I I is rotationauy oscillated relative to itslongitudinal axis; also, that considerably prolonged and rapidoscillation is possible in the construction described without damage tothe coupling structure or joint. I2 and without substantial transmissionloss.

A modification of the present invention, directed particularly to thepins and means of retaining them, is shown in Figs. 5-8. As there showneach pin 22b is similar to the pins 22a (of Figs. 3 and 4) alreadydescribed, except that, the neck portion 23b, of each pin 22b, extendingbeyond the section I3-I"I in which it is positioned, is of smallerdiameter than that. of the larger body portion 24?), located within oneof the recesses 2|, thereby defining an annular shoulder 25 (Fig. 8).

It is preferred to retain the pins 221) by mountingrelatively thin rings36 of metal or other suitable rigid material upon the circumferentialsurface of the sections, section I4 being shown for purposes ofillustration (Figs. 5-8) Ring 3d may be mounted on section I4 in anysuitable manner, such as by screws 3 I, or by keying, welding, etc., andits outside circumferential surface should make a sliding fit Within thesleeve 28.

Substantially circular apertures 32 corresponding to the number ofrecesses 2|, are provided in ring 36 and extend through the radial widthof ring 36 with the center of. apertures 32- lying on the radii of theindividual section I13 through the centers of recesses 21. The axialdimension of ring is preferably less than the axial length of section I4and less than the diametersof recesses 2| and of the body portions 24bof the pins 221). Thus, portions of ring. 30 adjacent apertures 32 willoverlap shoulders 25 and hold pins 222) in place within recesses 2|. Thediameter of apertures 32 is preferably less than the diameter ofrecesses 2 I, but larger than the axial length of ring 36; thus ineffect, if section 24 isprovided with two recesses 2|, ring 36 isdivided into two equal parts by two apertures 32, leaving diametricallyopposite spaces between said two parts. The remaining arc-shaped wallsat the opposing ends of the said two parts of ring 36, which defineapertures 32, partially surround and embrace the extending neck portions231) of pins 2217, thereby permitting pins 22b to rotatewithin apertures32. The radial width of ring 36; is

;. preferably substantially equal to the length of neck portion 23b.

While preferred embodiments of the present invention have beenillustrated and described, it will be understood these are capable ofmodification and improvement without departing from the spirit of theinvention. Therefore it is not desired that the scope of the inventionbe limited.

to the precise details set forth.

Having thus described the invention what we claim as new and desire tosecure by Letters Patent is:

1. A coupling structure for connecting a length. of stationary waveguide to a length of rotatable wave guide for transmissionofhigh-frequency energy comprising, in combination, a plurality ofsubstantially disc-shaped sections in aligned abutting relation, saidsections being rotatable relative toeach other in planes perpendicularto a common axis and having a plurality of equally spaced circularrecesses disposed in the circumferential surface portions of each ofsaid sections, said sections also having radio-fre-- quency chokecavities associated with Opposing faces thereof and aligned centralapertures correspending to the dimensions of said wave guides,

Said stationary wave guide and said rotatable wave guide being connectedto opposite end sec,- tions of said coupling structure in communica-,tion with said apertures in said end sections, a substantiallycylindrical pin member disposed in each of said recesses in saidsections with the axes of said pin members colinear with radii of saidsections, said pin members being free to rotate about their axes withinsaid recesses, a portion of each of said pin members extending radiallybeyond the circumference of saidsections and having a bore diametricallydisposed therein, the axis of each such bore being normally parallelwith the longitudinal axis of said structure, and a relatively flexiblewire extending sub.- stantially the length of said abutting sections andbeing in slidable engagement through said bores in aligned pin members,said wire being adapted to impart limited rotational movementsuccessively to said sections upon rotation in either direction of saidoscillating wave guide, said pin members rotating within theirassociated recesses due to angular displacement of said wire and therebyreducing the tendency of said wire to bend.

2. A coupling structure as claimed in claim 1 wherein a hollowcylindrical sleeve is mounted in closely fitting relation around thesections and is adapted to slidably engage the top surfaces of the pinmembers, thereby holding said pin members in position in their recesses.

3. A coupling structure as claimed in claim 1 wherein the sectionscomprise two end sections respectively secured to the stationary waveguide and the rotatable waveguide, a center section having smoothparallel faces, the axial width between said parallel faces being halfthe wavelength of the transmitted energy, and at least one intermediatesection between said center section and each of said end sections, theaxial width of such intermediate section being a quarter of thewavelength of said energy.

4. A coupling structure as claimed in claim 1 wherein a substantiallyring-shaped member is mounted on the circumferential surface of each ofthe sections, the axial width of said ringshaped member being less thanthe diameters of the recesses and of the pin members in each of saidsections, said ring-shaped member having a plurality of circularopenings extending through the radial dimension of said ring-shapedmember with the axes of said openings coinciding with the axes of saidpin members, the diameter of each of said openings being greater thanthe axial width of said ring-shaped member whereby said openingseffectively divide said ring-shaped member into a plurality of spacedarcuate portions, the walls of said openings partially sur-- roundingreduced extending portions of said pin members and overlapping theportions of said pin members within said recesses, thereby maintainingsaid pin members in position.

- 5. A coupling structure for connecting a length of stationary waveguide to a length of rotatable wave guide adapted to transmit highfrequency energy comprising, in combination, a plurality of relativelyshort substantially cylindrically shaped sections in aligned abuttingrelation, said sections being rotatable relative to each other in planesperpendicular to a common axis, said sections having radio frequencychoke cavities associated with opposing faces thereof and alignedcentral apertures corresponding to the dimensions of said wave guides,said stationary wave guide and said rotatable wave guide being connectedto opposite end sections of said coupling structure in communicationwith said apertures in said end sections, each of said sections having aplurality of angularly spaced recesses in the circumferential portionthereof, pin means loosely mounted in said recesses, and flexible meansslidably engaging said pin means, said flexible means being adapted toimpart limited rotation to said sections in either direction upon rota--tional oscillation of said rotatable wave guide.

6. A coupling structure for connecting a length of stationary wave guideto a length of rotatable wave guide adapted to transmit highfrequencyenergy comprising, in combination, a pluralityof relativelyshort substantially cylindricallyshaped sections in aligned abuttingrelation, said sections being rotatable relative to each other in planesperpendicular to a common axis, said sections having radio frequencychoke cavities associated with opposing faces thereof and alignedcentral apertures corresponding to the dimensions of said wave guides,said stationary wave guide and said rotatable wave guide being con--nected to opposite end sections of said coupling structure incommunication with said apertures in said end sections, each of saidsections having at least one recess in the circumferential portionthereof, said recesses in adjacent sections being in substantialalignment, rotatable means carried in each of said recesses and meansconnecting said rotatable means for imparting limited rotation to saidsections in either direction upon rotational oscillation of saidrotatable wave guide.

7. A joint for coupling two lengths of wave guide comprising, incombination, a plurality of abutting joint sections, means fortransmitting energy through said joint sections, choke means associatedwith said transmitting means for preventing leakage of energy from saidjoint sec-' tions, and means slidably mounted relative to said sectionsfor imparting and permitting progressively limited rotationaloscillation to said sections relative to one end of said joint whilemaintaining continuity of energy transmission through said joint.

8. In a structure for coupling together two wave guides which haveopposing extremities disposed in spaced coaxial relationship andrelatively rotatable about said common axis, a plurality of couplingsections, said sections including two end sections respectively joinedto and rotatable with the two extremities of said wave guides, and aplurality of intermediate sections disposed between said end sections,the consecu tive sections abutting each other, and each of said sectionsbeing provided with wave guidev means extending therethrough and coaxialwith the common axis aforesaid; means to maintain said sections in theirabutting relationship and to maintain the wave guide means thereof intheir coaxial relationship and to allow said sections to rotate relativeto each other about said common axis; and means joining consecutivesectionsand adapted to transmit angular displacements of the endsections relative to each other to the intermediate sections inprogressively limited amounts so that the angular displacements betweenconsecutive sections is relatively small.

9. In a coupling structure as defined in claim 8, wherein choke meansare provided to substantially prevent losses of energy betweensuccessive sections.

length of a wave guide for interconnecting sections thereof, comprisinga series of relatively rotatable individual members each having anopening generally corresponding in size and shape to the inside contourof the wave guide, a housing containing said members and means foreffecting rotation of said members successively and progressively in theevent of relative rotation of the interconnected wave guide sections,thus locating the openings in said members in different angularpositions to produce the effect of a twisted guide.

11. A device adapted to be inserted in the length of a wave guide forinterconnecting sections thereof, comprising a series of relativelyrotatable individual members each having an opening generallycorresponding in size and shape to the inside contour of the wave guide,a housing containing said members, and means interconnecting saidmembers and capable of rotating the same successively and progressivelyin the event of relative rotation of the intercom nec'ted wave guidesections, thus locating the openings in said members in differentangular positions to produce the effect of a twisted guide.

12. A device adapted, to be inserted between wave guide sections forinterconnecting the same, comprising a series of plates maintained infaceto-face relationship and rotatable with respect to each other abouta common axis, each of said plates having an opening generallycorresponding in size and shape to the inside contour of said sections,each of said plates further having re-- cesses therein, and meansincluding elements disposed in the recesses of said plates for effectingrotation of the plates successively and progressively in response torelative rotation of the interconnected wave guide sections.

13. In a device adapted to be inserted between wave guide sections forinterconnecting the same, a series of abutting rigid apertured membersarranged for relative rotation about a common axis and cooperativelyforming a wave guide, and means interlinking said members and operableto effect relative rotation thereof, to produce a twisting of the waveguide formed by said members, in response to relative rotation of theinterconnected wave guide sections.

WALTER A. ARON. CHARLES H. DAVIS. LOWELL M. HOLLINGSWORTH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Zaleski D80. 23, 1947

